The acoustic characteristics of acoustic products such as a speaker, a receiver, and a microphone in mobile terminal devices and the like change based on setting conditions. For example, in the speaker, a resonant frequency decreases and a sound volume on a low frequency side increases with an increase in the volume of the rear space (rear air chamber) of the speaker.
The volume of a space is obtained by a numerical analysis such as an electrothermal analysis, a mechanism analysis, or an electromagnetic field analysis for a structure. In the numerical analysis, for example, the numerical analysis is executed using a model for the numerical analysis that is generated by dividing the three-dimensional shape data of the structure into a large number of polyhedral elements using a predetermined mesh.
A related technique is disclosed in International Publication Pamphlet No. WO 2005/086034.